Method and apparatus for establishing proximity service communication in a wireless communication system

ABSTRACT

Methods and apparatuses are disclosed to establish proximity service communication between a first user equipment (UE) and a second UE. The method includes receiving, by the first UE, a signaling transmitted by an evolved Node B (eNB) to provide a radio resource for the first UE to transmit data directly to the second UE, wherein an indication of a Radio Network Temporary Identifier (RNTI) is included in the signaling. The method further includes transmitting, by the first UE, data via the radio resource to the second UE, wherein the data is scrambled by the RNTI.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/731,712 filed on Nov. 30, 2012, the entiredisclosure of which is incorporated herein by reference.

FIELD

This disclosure generally relates to wireless communication networks,and more particularly, to methods and apparatuses for establishingproximity service communication in a wireless communication system.

BACKGROUND

With the rapid rise in demand for communication of large amounts of datato and from mobile communication devices, traditional mobile voicecommunication networks are evolving into networks that communicate withInternet Protocol (IP) data packets. Such IP data packet communicationcan provide users of mobile communication devices with voice over IP,multimedia, multicast and on-demand communication services.

An exemplary network structure for which standardization is currentlytaking place is an Evolved Universal Terrestrial Radio Access Network(E-UTRAN). The E-UTRAN system can provide high data throughput in orderto realize the above-noted voice over IP and multimedia services. TheE-UTRAN system's standardization work is currently being performed bythe 3GPP standards organization. Accordingly, changes to the currentbody of 3GPP standard are currently being submitted and considered toevolve and finalize the 3GPP standard.

SUMMARY

Methods and apparatuses are disclosed to establish proximity servicecommunication between a first user equipment (UE) and a second UE. Themethod includes receiving, by the first UE, a signaling transmitted byan evolved Node B (eNB) to provide a radio resource for the first UE totransmit data directly to the second UE, wherein an indication of aRadio Network Temporary Identifier (RNTI) is included in the signaling.The method further includes transmitting, by the first UE, data via theradio resource to the second UE, wherein the data is scrambled by theRNTI.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of a wireless communication system according toone exemplary embodiment.

FIG. 2 is a block diagram of a transmitter system (also known as accessnetwork) and a receiver system (also known as user equipment or UE)according to one exemplary embodiment.

FIG. 3 is a functional block diagram of a communication system accordingto one exemplary embodiment.

FIG. 4 is a functional block diagram of the program code of FIG. 3according to one exemplary embodiment.

FIG. 5 is a block diagram of a direct mode data path in the EvolvedPacket System (EPS) for communication between two UEs.

FIG. 6 is a block diagram of a locally-routed data path in the EPS forcommunication between two UEs when the UEs are served by the sameevolved Node B (eNB).

FIG. 7 is an exemplary block diagram of a control path for networksupported ProSe communication for UEs served by the same eNB.

FIG. 8 is another exemplary block diagram of a control path for networksupported ProSe Communication for UEs served by different eNBs.

FIG. 9 is another exemplary block diagram of a control path for PublicSafety ProSe Communication for UEs without network support.

FIG. 10 is a signaling flow diagram according to one exemplaryembodiment.

FIG. 11 is a signaling flow diagram according to one exemplaryembodiment.

FIG. 12 is a signaling flow diagram according to one exemplaryembodiment.

FIG. 13 is a signaling flow diagram according to one exemplaryembodiment.

DETAILED DESCRIPTION

The exemplary wireless communication systems and devices described belowemploy a wireless communication system, supporting a broadcast service.Wireless communication systems are widely deployed to provide varioustypes of communication such as voice, data, and so on. These systems maybe based on code division multiple access (CDMA), time division multipleaccess (TDMA), orthogonal frequency division multiple access (OFDMA),3GPP LTE (Long Term Evolution) wireless access, 3GPP LTE-A orLTE-Advanced (Long Term Evolution Advanced), 3GPP2 UMB (Ultra MobileBroadband), WiMax, or some other modulation techniques.

In particular, the exemplary wireless communication systems devicesdescribed below may be designed to support one or more standards such asthe standard offered by a consortium named “3rd Generation PartnershipProject” referred to herein as 3GPP, including Document Nos. RP-121435,“Study on LTE Device to Device Proximity Discovery”; TR 22.803 V1.0.0,“Feasibility Study for Proximity Services (ProSe)”; TS 36.331 V11.1.0,“E-UTRA RRC protocol specification”; TS 36.321 V11.0.0, “E-UTRA MACprotocol specification”; and TS 36.213 V11.0.0, “E-UTRA Physical layerprocedures”. The standards and documents listed above are herebyexpressly incorporated herein.

FIG. 1 shows a multiple access wireless communication system accordingto one embodiment of the invention. An access network 100 (AN) includesmultiple antenna groups, one including 104 and 106, another including108 and 110, and an additional including 112 and 114. In FIG. 1, onlytwo antennas are shown for each antenna group, however, more or fewerantennas may be utilized for each antenna group. Access terminal 116(AT) is in communication with antennas 112 and 114, where antennas 112and 114 transmit information to access terminal 116 over forward link120 and receive information from access terminal 116 over reverse link118. Access terminal (AT) 122 is in communication with antennas 106 and108, where antennas 106 and 108 transmit information to access terminal(AT) 122 over forward link 126 and receive information from accessterminal (AT) 122 over reverse link 124. In a FDD system, communicationlinks 118, 120, 124 and 126 may use different frequency forcommunication. For example, forward link 120 may use a differentfrequency then that used by reverse link 118.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the access network. Inthe embodiment, antenna groups each are designed to communicate toaccess terminals in a sector of the areas covered by access network 100.

In communication over forward links 120 and 126, the transmittingantennas of access network 100 may utilize beamforming in order toimprove the signal-to-noise ratio of forward links for the differentaccess terminals 116 and 122. Also, an access network using beamformingto transmit to access terminals scattered randomly through its coveragecauses less interference to access terminals in neighboring cells thanan access network transmitting through a single antenna to all itsaccess terminals.

An access network (AN) may be a fixed station or base station used forcommunicating with the terminals and may also be referred to as anaccess point, a Node B, a base station, an enhanced base station, aneNodeB, or some other terminology. An access terminal (AT) may also becalled user equipment (UE), a wireless communication device, terminal,access terminal or some other terminology.

FIG. 2 is a simplified block diagram of an embodiment of a transmittersystem 210 (also known as the access network) and a receiver system 250(also known as access terminal (AT) or user equipment (UE)) in a MIMOsystem 200. At the transmitter system 210, traffic data for a number ofdata streams is provided from a data source 212 to a transmit (TX) dataprocessor 214.

In one embodiment, each data stream is transmitted over a respectivetransmit antenna. TX data processor 214 formats, codes, and interleavesthe traffic data for each data stream based on a particular codingscheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by processor 230.

The modulation symbols for all data streams are then provided to a TXMIMO processor 220, which may further process the modulation symbols(e.g., for OFDM). TX MIMO processor 220 then provides N_(T) modulationsymbol streams to N_(T) transmitters (TMTR) 222 a through 222 t. Incertain embodiments, TX MIMO processor 220 applies beamforming weightsto the symbols of the data streams and to the antenna from which thesymbol is being transmitted.

Each transmitter 222 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from transmitters 222 a through 222 t are thentransmitted from N_(T) antennas 224 a through 224 t, respectively.

At receiver system 250, the transmitted modulated signals are receivedby N_(R) antennas 252 a through 252 r and the received signal from eachantenna 252 is provided to a respective receiver (RCVR) 254 a through254 r. Each receiver 254 conditions (e.g., filters, amplifies, anddownconverts) a respective received signal, digitizes the conditionedsignal to provide samples, and further processes the samples to providea corresponding “received” symbol stream.

An RX data processor 260 then receives and processes the N_(R) receivedsymbol streams from N_(R) receivers 254 based on a particular receiverprocessing technique to provide N_(T) “detected” symbol streams. The RXdata processor 260 then demodulates, deinterleaves, and decodes eachdetected symbol stream to recover the traffic data for the data stream.The processing by RX data processor 260 is complementary to thatperformed by TX MIMO processor 220 and TX data processor 214 attransmitter system 210.

A processor 270 periodically determines which pre-coding matrix to use(discussed below). Processor 270 formulates a reverse link messagecomprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message is then processed by a TX data processor 238, whichalso receives traffic data for a number of data streams from a datasource 236, modulated by a modulator 280, conditioned by transmitters254 a through 254 r, and transmitted back to transmitter system 210.

At transmitter system 210, the modulated signals from receiver system250 are received by antennas 224, conditioned by receivers 222,demodulated by a demodulator 240, and processed by a RX data processor242 to extract the reserve link message transmitted by the receiversystem 250. Processor 230 then determines which pre-coding matrix to usefor determining the beamforming weights then processes the extractedmessage.

Turning to FIG. 3, this figure shows an alternative simplifiedfunctional block diagram of a communication device according to oneembodiment of the invention. As shown in FIG. 3, the communicationdevice 300 in a wireless communication system can be utilized forrealizing the UEs (or ATs) 116 and 122 in FIG. 1, and the wirelesscommunications system is preferably the LTE system. The communicationdevice 300 may include an input device 302, an output device 304, acontrol circuit 306, a central processing unit (CPU) 308, a memory 310,a program code 312, and a transceiver 314. The control circuit 306executes the program code 312 in the memory 310 through the CPU 308,thereby controlling an operation of the communications device 300. Thecommunications device 300 can receive signals input by a user throughthe input device 302, such as a keyboard or keypad, and can outputimages and sounds through the output device 304, such as a monitor orspeakers. The transceiver 314 is used to receive and transmit wirelesssignals, delivering received signals to the control circuit 306, andoutputting signals generated by the control circuit 306 wirelessly.

FIG. 4 is a simplified block diagram of the program code 312 shown inFIG. 3 in accordance with one embodiment of the invention. In thisembodiment, the program code 312 includes an application layer 400, aLayer 3 portion 402, and a Layer 2 portion 404, and is coupled to aLayer 1 portion 406. The Layer 3 portion 402 generally performs radioresource control. The Layer 2 portion 404 generally performs linkcontrol. The Layer 1 portion 406 generally performs physicalconnections.

For LTE or LTE-A systems, the Layer 2 portion may include a Radio LinkControl (RLC) layer and a Medium Access Control (MAC) layer. The Layer 3portion may include a Radio Resource Control (RRC) layer.

Device to device discovery (as discussed in RP-121435) and communicationfor proximity services are expected to be an important feature for LTEin future, e.g. in Rel-12. The discussion on the feasibility study forProximity Services (ProSe) is ongoing and is discussed in 3GPP TR 22.803V1.0.0. The objective of the study is quoted below:

-   -   The objective is to study use cases and identify potential        requirements for operator network controlled discovery and        communications between UEs that are in proximity, under        continuous network control, and are under 3GPP network coverage,        for:        -   1. Commercial/social use        -   2. Network offloading        -   3. Public Safety        -   4. Integration of current infrastructure services, to assure            the consistency of the user experience including            reachability and mobility aspects    -   Additionally, the study item will study use cases and identify        potential requirements for        -   5. Public Safety, in case of absence of EUTRAN coverage            (subject to regional regulation and operator policy, and            limited to specific public-safety designated frequency bands            and terminals)

As discussed in 3GPP TR 22.803 V1.0.0, ProSe includes two mainfunctions: ProSe Discovery and ProSe Communication. ProSe Discovery is aprocess that identifies that a UE is in proximity of another UE usingEvolved Universal Terrestrial Radio Access (E-UTRA). ProSe Discoveryshall support a minimum of three range classes—for example short, mediumand maximum range. ProSe Communication is a communication between twoUEs in proximity by means of a communication path established betweenthe UEs. For example, the communication path could be establisheddirectly between the UEs or routed via local evolved Node B(s) (eNB(s)).

A UE that supports ProSe Discovery and/or ProSe Communication is calleda ProSe-enabled UE.

ProSe Discovery may be either Open ProSe Discovery or Restricted ProSeDiscovery. Open ProSe Discovery does not need explicit permission fromthe UE being discovered. Restricted ProSe Discovery needs explicitpermission from the UE being discovered.

FIGS. 5 and 6 illustrate possible data paths for ProSe Communications.FIG. 5 illustrates a direct mode data path in the Evolved Packet System(EPS) for communication between two UEs 510, 520 in a system 500 iscomposed of two UEs 510, 520, two evolved Node B's (eNBs) 540, 550 and aserving gateway and/or packet data network gateway (SGW/PGW) 560. FIG. 6illustrates a locally-routed data path in the EPS for communicationbetween two UEs 510, 520 when the UEs are served by the same eNB 540. InFIG. 6, the system 600 may be composed of two UEs 510, 520, two eNBs540, 550, and a SGW/PGW 560.

FIGS. 7-9 illustrate possible control paths for ProSe Communications.FIG. 7 is an exemplary block diagram of a control path for networksupported ProSe communication for UEs 510, 520 served by the same eNB540. As shown in FIG. 7, the UEs 510, 520 communicate with the same eNB540, which in turn communicates with an Evolved Packet Core (EPC) 710.FIG. 8 is another exemplary block diagram of a control path for networksupported ProSe Communication for UEs 510, 520 served by different eNBs540, 550. As shown in FIG. 8, a first UE 510 communicates with a firsteNB 540, and the second UE 520 communicated with a second eNB 550. Eachof the eNBs 540, 550 then communicates with the EPC 710. FIG. 9 isanother exemplary block diagram of a control path for Public SafetyProSe Communication for UEs 510, 520 without network support. As shownin FIG. 9, the UEs 510, 520 communicate with a Public Safety RadioResource Controller 910. Alternatively, for public safety purposes, aPublic Safety UE can relay the radio resource management controlinformation for other Public Safety UEs that do not have networkcoverage.

As discussed in 3GPP TR 22.803 V1.0.0 provides some ProSe Communicationrequirements as quoted below:

5.1.6.5 Potential Requirements

Requirements for E-UTRA ProSe Communications

-   -   The system shall be capable of establishing a new user traffic        session with an E-UTRA ProSe Communication path, and maintaining        both of the E-UTRA ProSe Communication path and the        infrastructure path simultaneously, when the UEs are determined        to be in range allowing ProSe Communication.        -   Note: ProSe specifications should take into account the            relative speed of ProSe-enabled UEs.    -   The system shall be capable of moving a user traffic session        from the infrastructure path to an E-UTRA ProSe Communication        path, when the ProSe-enabled UEs are determined to be in range        allowing ProSe Communication.    -   The system shall be capable of monitoring the communication        characteristics (e.g. channel condition, QoS of the path, volume        of the traffic etc.) on the E-UTRA ProSe communication path,        regardless of whether there is data transferred via        infrastructure path.    -   The system shall be capable of moving a user traffic session        from an E-UTRA ProSe communication path to an infrastructure        path. At a minimum, this functionality shall support the case        when the E-UTRA ProSe Communication path is no longer feasible.        The user shall not perceive the switching of user traffic        sessions between the E-UTRA ProSe Communication and        infrastructure paths.    -   The system shall be capable of switching each flow it is aware        of between the E-UTRA ProSe Communication and the infrastructure        paths, independently.    -   The establishment of a user traffic session on the E-UTRA ProSe        Communication path and the switching of user traffic between an        E-UTRA Prose Communication path and an infrastructure path are        under control of the network.    -   The Radio Access Network shall control the radio resources        associated with the E-UTRA ProSe Communication path.    -   The ProSe mechanism shall allow the operator to change the        communication path of a user traffic session without affecting        the QoS of the session.    -   The ProSe mechanism shall allow the operator to change the        communication path of one user traffic session of a UE without        affecting the communication paths of other ongoing user traffic        sessions.    -   The ProSe mechanism shall allow the operator to change the        communication path of a user traffic session according to        decisions based upon the QoS requirements of the session and the        QoS requirements of other ongoing sessions.    -   The system shall be capable of selecting the most appropriate        communications path, according to operator preferences. The        criteria for evaluation may include the following, although not        restricted to:        -   System-specific conditions: backhaul link, supporting links            or core node (EPC) performance;        -   Cell-specific conditions: cell loading;        -   UE to UE conditions: communication range, channel conditions            and achievable QoS;        -   UE to eNB conditions: communication range, channel            conditions and achievable QoS;        -   Service-type conditions: APN, service discriminator.

6.2 Additional Operational Requirements

-   -   ProSe services are available to ProSe-enabled UEs that are        registered to a PLMN, and are under coverage of the E-UTRAN of        said PLMN, potentially served by different eNBs. In this case        E-UTRAN resources involved in ProSe services will be under real        time 3GPP network control.    -   Subject to operator policy and user consent, a ProSe-enabled UE        should be capable of establishing the E-UTRAN infrastructure        path and ProSe communication path concurrently.    -   The network should be able to collect Discovery information        regarding which ProSe-enabled UEs are discovered to be in        proximity of a given UE. Restrictions from contracts and        regulation on data collection apply.    -   ProSe services are not available to ProSe-enabled UEs out of        E-UTRAN coverage except in the following case:    -   ProSe-enabled public safety UEs can use ProSe services when        operating on public safety spectrum dedicated to ProSe services        even when not under E-UTRAN coverage. In this case, at least a        one-time pre-authorization to use ProSe services is needed.    -   Re-authorization and specific configurations, including spectrum        configurations, of public safety UEs shall be subject to public        safety operator policy.    -   When Operating ProSe, the EPS shall be able to support regional        or national regulatory requirements, (e.g. lawful interception,        PWS).

6.3 Additional Charging Requirements

-   -   When a ProSe-enabled UE uses ProSe Communication, the operator        shall be able to collect accounting data for ProSe communication        including:        -   activation/deactivation of the ProSe Communication feature        -   ProSe Communication initiation/termination        -   ProSe Communication duration, and amount of data transferred    -   The above requirements do not apply to public safety        communications outside network coverage.

In the wireless communication technology, there are methods fortransmission and reception of proximity detection signal for peerdiscovery. In one method, peer discovery is a UE performs peer discoverywith the assistance from the network. The network may send anotification to the UE of a match for the UE seeking a peer.Additionally, the notification may also convey resources and/or otherparameters to use for peer discovery. Upon receiving the notification,the UE may then perform peer discovery using proximity detectionsignals. In one design, the proximity detection signal is based on thePhysical Uplink Shared Channel (PUSCH), which includes a proximitydetection reference signal and a data portion. The data portion of theproximity detection signal may include information such as identity ofthe UE transmitting the proximity detection signal, services requestedby the UE, services offered by the UE, and/or location information forthe UE.

In the wireless communication technology, methods for indicatingwireless network resources for communicating peer discovery signals areknown. These methods provide exemplary time structures and channels thatmay be utilized for peer-to-peer discovery and communication. The timestructures may have varying levels of frames of time, in which eachlower frame level is further subdivided into different periods of time.Similarly, the channels for peer discovery may be subdivided intosubchannels, in which each of the subchannels may be composed of aplurality of blocks for communicating peer discovery information. Forexample, a peer discovery channel may include subchannels such as a longrange peer discovery channel, medium range peer discovery channel, or ashort range peer discovery channel.

When a UE is turned on, the UE listens to the peer discovery channel andselects a set of blocks from a subchannel. Depending upon the characterof the subchannel, the UE may transmit peer discovery signals or listenfor peer discovery signals sent from other UEs.

Currently, only use cases and requirements for ProSe Communication arespecified in 3GPP TR 22.803 V1.0.0. Methods to realize ProSeCommunication and fulfil those requirements are not yet designed. Onemain difference compared to the existing peer to peer connectiontechnologies, such as Bluetooth, WiFi ad hoc, WiFi Direct, or the like,is that LTE network should be in control of the ProSe Communicationfunctions. For example, the LTE network should be in control ofestablishing of a new user traffic session with an E-UTRA ProSeCommunication path; moving a user traffic session between infrastructurepath and E-UTRA ProSe Communication path; real time control for theradio resources associated with the E-UTRA ProSe Communication path;and/or collecting accounting data including activation/deactivation ofthe ProSe Communication feature, ProSe Communicationinitiation/termination, and ProSe Communication duration, and amount ofdata transferred.

In order to realize ProSe Communication with involvement of networkcontrol, new signaling is required. According to various embodiments,the content of the signaling and the signaling flow is designed tofulfil requirements for ProSe Communication as set forth in 3GPP TR22.803 V1.0.0. Additionally, the various embodiments disclosed hereinprovide ProSe Communication based on existing mechanisms, e.g.procedures, channels, or etc., as many as possible to reduce thecomplexity of introducing ProSe Communication into LTE.

Signaling

In one embodiment, UE1 and UE2 connect to eNB(s). When UE1 communicateswith UE2 via ProSe Communication, one or multiple signaling describedbelow ((a)-(h)) may be used, for example, to support dynamic scheduling,Semi-Persistent scheduling, or retransmission.

(a) A Signaling Transmitted by eNB Provides Radio Resource, e.g. UplinkGrant, for UE1 to Transmit Data Directly to UE2.

In one embodiment, the signaling can be a Physical Downlink ControlChannel (PDCCH) or Enhanced Physical Downlink Control Channel (EPDCCH)signaling (as described in 3GPP TS 36.321 V11.0.0 and 3GPP TS 36.213V11.0.0).

In one embodiment, the signaling may be addressed to a (pre-configured)Radio Network Temporary Identifier (RNTI) for ProSe Communication, UE1'sCell Radio Network Temporary Identifier (C-RNTI) (as described in 3GPPTS 36.321 V11.0.0), or Semi-Persistent Scheduling Radio NetworkTemporary Identifier (SPS-RNTI) (as described in 3GPP TS 36.321V11.0.0).

In embodiment, the signaling may include an indication to indicate that(1) the radio resource is for ProSe Communication; (2) the RNTI, e.g. a(pre-configured) RNTI for ProSe Communication or UE1's C-RNTI or UE2'sC-RNTI or SPS-RNTI, be used to scramble data transmitted via the radioresource; (3) the power (setting) to be used to transmit data via theradio resource, e.g. using power (setting) corresponding to ProSeCommunication; (4) the radio resource is used to carry data from aspecific Radio Bearer (RB) (as described in 3GPP TS 36.331 V11.1.0); or(5) the RB for which its data can be carry by the radio resource.

Based on the indication, UE1 may use a different calculation method(i.e., comparing with uplink grant allocation signaling forinfrastructure path) to derive the radio resource from the signaling.

(b) A Signaling Transmitted by eNB Indicates UE2 to Receive a DataTransmission Directly from UE1, e.g., See (c) Below.

In one embodiment, the signaling can be a PDCCH or EPDCCH signaling,e.g. for downlink assignment.

In one embodiment, the signaling may be addressed to a (pre-configured)RNTI for ProSe Communication, UE2's C-RNTI, or SPS-RNTI.

In one embodiment, the signaling may include an indication to indicatethat (1) the data transmission is ProSe Communication; (2) the RNTI,e.g. a (pre-configured) RNTI for ProSe Communication or UE1's C-RNTI orUE2's C-RNTI or SPS-RNTI, to be used to de-scramble the data; (3) thepower (setting) to be used to transmit an acknowledgement for receptionof the data, e.g. using power (setting) corresponding to ProSeCommunication; or (4) the key(s) and/or algorithm(s) (as described in3GPP TS 36.331 V11.1.0) to be used to decipher the data and/or check theintegrity of the data.

Based on the indication, UE2 may use different calculation method(comparing with downlink assignment signaling for infrastructure path)to derive the radio resource used to transmit the data from thesignaling.

In an alternate embodiment, the signaling may not always be required fora data transmission if Semi-Persistent Scheduling (as described in 3GPPTS 36.321 V11.0.0) is used.

(c) Data Directly Transmitted from UE1 to UE2 Via the Received RadioResource.

In one embodiment, the radio resource (only) carries data from a(preconfigured) specific RB(s). The data from those RB(s) may not be(allowed to be) carried by radio resource not for ProSe Communication.

In one embodiment, the radio resource does not carry one or more of thefollowing: the Buffer Status Report (BSR) (as described in 3GPP TS36.321 V11.0.0), Power Headroom Report (PHR) (as described in 3GPP TS36.321 V11.0.0), Channel Quality Indicator (CQI), and/or Channel StateInformation (CSI).

In one embodiment, UE1 may use PUSCH or a channel for ProSeCommunication to transmit the data.

In one embodiment, the data may be scrambled by a (pre-configured) RNTIfor ProSe Communication or UE1's C-RNTI or UE2's C-RNTI or SPS-RNTI.

In one embodiment, UE2 may receive (b) and (c), as described above, inthe same TTI.

In one embodiment, UE2 may receive (g) as described below and (c) asdescribed above in the same TTI.

(d) Providing an Acknowledgement, e.g. Hybrid Automatic Repeat RequestAcknowledgement (HARQ ACK) or Negative Acknowledgement (NACK) (asDescribed in 3GPP TS 36.321 V11.0.0), by UE2 to Indicate Whether theReception of the Data is Successful or not.

In one embodiment, the acknowledgement can be transmitted via PhysicalUplink Control Channel (PUCCH).

In one embodiment, UE1 and/or eNB may receive the acknowledgement.

In one embodiment, UE1 may use different calculation method (comparingwith reception of PHICH) to derive the radio resource used to transmitthe acknowledgement from (a), as described above.

In one embodiment, the radio resource used to transmit theacknowledgement may be pre-configured.

In one embodiment, the interval between (a) and (d) (as describedherein) may be eight (8) subframes (Frequency Division Duplex (FDD)) ork+4 subframes (Time Division Duplex (TDD)) (as described in 3GPP TS36.213 V11.0.0).

(e) A Signaling Transmitted by eNB Indicates to UE2 to Receive aRetransmission of the Data Directly from UE1, e.g., See (f) as DescribedBelow.

In one embodiment, the signaling may be addressed to a (pre-configured)RNTI for ProSe Communication, UE2's C-RNTI, or SPS-RNTI.

In one embodiment, the signaling may be transmitted if anacknowledgement with NACK was received, for example as described in (d)above.

(f) Data Directly Retransmitted from UE1 to UE2.

In one embodiment, UE1 may use PUSCH or a channel for ProSeCommunication to retransmit the data.

In one embodiment, the data may be scrambled by a (pre-configured) RNTIfor ProSe Communication or UE1's C-RNTI or UE2's C-RNTI or SPS-RNTI.

In one embodiment, the retransmission may be transmitted if anacknowledgement with NACK was received, as described in (d) above.

In one embodiment, the interval between (c) as described above and (f)described herein may be eight (8) subframes (FDD) or k+4 subframes(TDD).

In one embodiment, UE2 may receive (e) as described above and (f) asdescribed herein in the same TTI.

In one embodiment, UE2 may receive (h) as describe below and (f) asdescribed herein in the same TTI.

(g) A Signaling Transmitted by UE1 Indicates UE2 to Receive a DataTransmission Directly from UE1, e.g., See (c) as Described Above.

In one embodiment, the signaling can be a Physical Downlink ControlChannel (PDCCH) signaling or Enhanced Physical Downlink Control Channel(EPDCCH) signaling or a signaling transmitted via a control channel forProSe Communication, e.g. for downlink assignment.

In one embodiment, the signaling may be addressed to a (pre-configured)RNTI for ProSe Communication, UE2's C-RNTI, or SPS-RNTI.

In one embodiment, the signaling may include an indication to indicate:(1) the data transmission is ProSe Communication; (2) the RNTI, e.g. a(pre-configured) RNTI for ProSe Communication or UE1's C-RNTI [4] orUE2's C-RNTI [4] or SPS-RNTI [4], to be used to de-scramble the data;(3) the power (setting) to be used to transmit an acknowledgement forreception of the data, e.g. using power (setting) corresponding to ProSeCommunication; or (4) the key(s) and/or algorithm(s) to be used todecipher the data and/or check the integrity of the data.

Based on the indication, UE2 may use different calculation method(comparing with downlink assignment signaling for infrastructure path)to derive the radio resource used to transmit the data from thesignaling.

In some embodiments, the signaling may not always be required for a datatransmission if Semi-Persistent Scheduling is used.

(h) a Signaling Transmitted by UE1 Indicates UE2 to Receive aRetransmission of the Data Directly from UE1, e.g., See (f) as DescribedAbove.

In one embodiment, the signaling may be addressed to a (pre-configured)RNTI for ProSe Communication, UE2's C-RNTI, or SPS-RNTI.

In one embodiment, the signaling may be transmitted if anacknowledgement with NACK was received, e.g. see (d) as described above.

In one embodiment, UE1 and UE2 may connect to different eNBs, forexample, UE1 is connected to eNB1 and UE2 is connected to eNB2.Accordingly, signaling as described in (a) and (b) may be transmitted bydifferent eNBs. By way of example and not of limitation, signal (a) istransmitted by a first eNB and signal (b) is transmitted by a secondeNB.

In one embodiment, the UE transmission power used for ProSeCommunication is controlled by eNB. In one embodiment, eNB may be basedon the channel condition report, e.g. CQI/CSI report, for ProSeCommunication received from the UE to change the transmission power. Forexample, but not of limitation, UE2 may provide a report to eNB based onthe measurement of the channel condition between UE1 and UE2. Then, eNBadjusts the transmission power of UE1 based on the received report.

In one embodiment, the ProSe Communication mentioned above can be E-UTRAProSe Communication. In some embodiments, the ProSe Communicationdescribed above uses a path directly between UEs.

Signaling Flow.

FIGS. 10-13 illustrate various embodiments of signaling flow to realizeProSe Communication. In FIG. 10, eNB 1030 provides a radio resource1040, e.g. via PDCCH, for UE1 1020 to transmit data to UE2 1010. Asshown in FIG. 10, eNB 1030 transmits a signaling 1050, e.g. via PDCCH,to inform UE2 1010 to receive a new data transmission, and UE1 1020transmits data 1060 via the received radio resource to UE2 1010. UE21010 responds with an acknowledgement 1070, e.g. via PUCCH, to indicatewhether the data is received correctly or not. As shown in FIG. 10, UE11020 and eNB 1030 may decide whether to perform retransmission 1080,1090 based on the received acknowledgement 1070.

In FIG. 11, eNB 1030 provides a radio resource 1040, e.g. via PDCCH, forUE1 1020 to transmit data to UE2 1010. As shown in FIG. 11, UE1 1020transmits a signaling 1120 to inform UE2 1010 to receive a new datatransmission, and UE1 transmits data 1060 via the received radioresource to UE2. UE2 1010 responds with an acknowledgement 1070, e.g.via PUCCH, to indicate whether the data is received correctly or not.UE1 1020 may decide whether to transmit an indication of dataretransmission 1090 and perform retransmission 1130 based on thereceived acknowledgement 1070. Optionally, eNB may monitor theacknowledgement 1110 to evaluate channel quality or QoS.

In FIG. 12, the eNB 1030 provides a radio resource 1040, e.g. via PDCCH,for UE1 1020 to transmit data to UE2 1010. As shown in FIG. 12, eNB 1030transmits a signaling 1050, e.g. via PDCCH, to inform UE2 1010 toreceive a new data transmission, and UE1 1020 transmits data 1060 viathe received radio resource to UE2 1010. UE2 1010 responds with anacknowledgement 1070, e.g. via PUCCH, to indicate whether the data isreceived correctly or not. UE1 1020 may decide whether to performretransmission 1090 in a fixed timing based on the receivedacknowledgement. Since the retransmission timing is known by UE2 1010,no signaling to inform a retransmission is required. Optionally, eNB1030 may monitor the acknowledgement 1110 to evaluate channel quality orQoS.

In FIG. 13, eNB 1030 provides a radio resource 1040, e.g. via PDCCH, forUE1 1020 to transmit data to UE2 1010. As shown in FIG. 13, UE1 1020transmits a signaling 1120 to inform UE2 1010 to receive a new datatransmission, and UE1 transmits data 1060 via the received radioresource to UE2. UE2 1010 responds with an acknowledgement 1070, e.g.via PUCCH, to indicate whether the data is received correctly or not.UE1 1020 may decide whether to perform retransmission 1090 in a fixedtiming based on the received acknowledgement. Since the retransmissiontiming is known by UE2 1010, no signaling to inform a retransmission isrequired. Optionally, eNB 1030 may monitor the acknowledgement 1110 toevaluate channel quality or QoS.

Referring back to FIGS. 3 and 4, the device 300 includes a program code312 stored in memory 310. In one embodiment, the CPU 308 could executethe program code 312 (i) to receive, by the first UE, a signalingtransmitted by a eNB to provide radio resource for the first UE totransmit data directly to the second UE, wherein an indication of a RNTIis included in the signaling, and (ii) to transmit, by the first UE,data via the radio resource to the second UE, wherein the data isscrambled by the RNTI. In another embodiment, the CPU 308 could executethe program code 312 (i) to receive, by the first UE, a first signalingtransmitted by a eNB to provide radio resource for the first UE totransmit data directly to the second UE, (ii) to transmit, by the firstUE, a second signaling to the second UE to inform the second UE toreceive data directly transmitted from the first UE, and (iii) totransmit, by the first UE, the data via the radio resource to the secondUE.

In addition, the CPU 308 can execute the program code 312 to perform allof the above-described actions and steps or others described herein.

Various aspects of the disclosure have been described above. It shouldbe apparent that the teachings herein may be embodied in a wide varietyof forms and that any specific structure, function, or both beingdisclosed herein is merely representative. Based on the teachings hereinone skilled in the art should appreciate that an aspect disclosed hereinmay be implemented independently of any other aspects and that two ormore of these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein. As an exampleof some of the above concepts, in some aspects concurrent channels maybe established based on pulse repetition frequencies. In some aspectsconcurrent channels may be established based on pulse position oroffsets. In some aspects concurrent channels may be established based ontime hopping sequences. In some aspects concurrent channels may beestablished based on pulse repetition frequencies, pulse positions oroffsets, and time hopping sequences.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, processors, means, circuits, and algorithmsteps described in connection with the aspects disclosed herein may beimplemented as electronic hardware (e.g., a digital implementation, ananalog implementation, or a combination of the two, which may bedesigned using source coding or some other technique), various forms ofprogram or design code incorporating instructions (which may be referredto herein, for convenience, as “software” or a “software module”), orcombinations of both. To clearly illustrate this interchangeability ofhardware and software, various illustrative components, blocks, modules,circuits, and steps have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentdisclosure.

In addition, the various illustrative logical blocks, modules, andcircuits described in connection with the aspects disclosed herein maybe implemented within or performed by an integrated circuit (“IC”), anaccess terminal, or an access point. The IC may comprise a generalpurpose processor, a digital signal processor (DSP), an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA) or other programmable logic device, discrete gate or transistorlogic, discrete hardware components, electrical components, opticalcomponents, mechanical components, or any combination thereof designedto perform the functions described herein, and may execute codes orinstructions that reside within the IC, outside of the IC, or both. Ageneral purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

It is understood that any specific order or hierarchy of steps in anydisclosed process is an example of a sample approach. Based upon designpreferences, it is understood that the specific order or hierarchy ofsteps in the processes may be rearranged while remaining within thescope of the present disclosure. The accompanying method claims presentelements of the various steps in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

The steps of a method or algorithm described in connection with theaspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module (e.g., including executable instructions and relateddata) and other data may reside in a data memory such as RAM memory,flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a harddisk, a removable disk, a CD-ROM, or any other form of computer-readablestorage medium known in the art. A sample storage medium may be coupledto a machine such as, for example, a computer/processor (which may bereferred to herein, for convenience, as a “processor”) such theprocessor can read information (e.g., code) from and write informationto the storage medium. A sample storage medium may be integral to theprocessor. The processor and the storage medium may reside in an ASIC.The ASIC may reside in user equipment. In the alternative, the processorand the storage medium may reside as discrete components in userequipment. Moreover, in some aspects any suitable computer-programproduct may comprise a computer-readable medium comprising codesrelating to one or more of the aspects of the disclosure. In someaspects a computer program product may comprise packaging materials.

While the invention has been described in connection with variousaspects, it will be understood that the invention is capable of furthermodifications. This application is intended to cover any variations,uses or adaptation of the invention following, in general, theprinciples of the invention, and including such departures from thepresent disclosure as come within the known and customary practicewithin the art to which the invention pertains.

1. A method for establishing proximity service communication between afirst user equipment (UE) and a second UE, the method comprising:receiving, by the first UE, a signaling transmitted by an evolved Node B(eNB) to provide a radio resource for the first UE to transmit datadirectly to the second UE, wherein an indication of a Radio NetworkTemporary Identifier (RNTI) is included in the signaling; andtransmitting, by the first UE, data via the radio resource to the secondUE, wherein the data is scrambled by the RNTI.
 2. The method of claim 1,wherein the signaling is a Physical Downlink Control Channel (PDCCH) orEnhanced Physical Downlink Control Channel (EPDCCH) signaling.
 3. Themethod of claim 1, wherein an indication about the radio resource is forthe proximity service communication is included in the signaling.
 4. Themethod of claim 1, wherein an indication of power to be used to transmitthe data is included in the signaling.
 5. The method of claim 1, whereinan indication of a radio bearer, whose data to be carried by the radioresource, is included in the signaling.
 6. A communication device forestablishing proximity service communication between the communicationdevice and a user equipment (UE), the communication device comprising: acontrol circuit; a processor installed in the control circuit; a memoryinstalled in the control circuit and operatively coupled to theprocessor; wherein the processor is configured to execute a program codestored in memory to establish the proximity service communication by:receiving a signaling transmitted by an evolved Node B (eNB) to providea radio resource for the communication device to transmit data directlyto the UE, wherein an indication of a Radio Network Temporary Identifier(RNTI) is included in the signaling; and transmitting data via the radioresource to the UE, wherein the data is scrambled by the RNTI.
 7. Thecommunication device of claim 6, wherein the signaling is a PhysicalDownlink Control Channel (PDCCH) or Enhanced Physical Downlink ControlChannel (EPDCCH) signaling.
 8. The communication device of claim 6,wherein an indication about the radio resource is for the proximityservice communication is included in the signaling.
 9. The communicationdevice of claim 6, wherein an indication of power to be used to transmitthe data is included in the signaling.
 10. The communication device ofclaim 6, wherein an indication of a radio bearer, whose data to becarried by the radio resource, is included in the signaling.
 11. Amethod for establishing proximity service communication between a firstuser equipment (UE) and a second UE, the method comprising: receiving,by the first UE, a first signaling transmitted by an evolved Node B(eNB) to provide a radio resource for the first UE to transmit datadirectly to the second UE; transmitting, by the first UE, a secondsignaling to the second UE to inform the second UE to receive datadirectly transmitted from the first UE; and transmitting, by the firstUE, the data via the radio resource to the second UE.
 12. The method ofclaim 11, wherein the second signaling is a Physical Downlink ControlChannel (PDCCH) or Enhanced Physical Downlink Control Channel (EPDCCH)signaling or a signaling transmitted via a control channel for theproximity service communication.
 13. The method of claim 11, wherein anindication of a Radio Network Temporary Identifier (RNTI) to be used tode-scramble the data is included in the second signaling.
 14. The methodof claim 11, wherein an indication of power to be used to transmit anacknowledgement for reception of the data is included in the secondsignaling.
 15. The method of claim 11, wherein an indication of a keyand/or an algorithm to be used to decipher the data and/or check theintegrity of the data is included in the second signaling.
 16. Acommunication device for establishing proximity service communicationbetween the communication device and a user equipment (UE), thecommunication device comprising: a control circuit; a processorinstalled in the control circuit; a memory installed in the controlcircuit and operatively coupled to the processor; wherein the processoris configured to execute a program code stored in memory to establishthe proximity service communication by: receiving a first signalingtransmitted by an evolved Node B (eNB) to provide a radio resource forthe communication device to transmit data directly to the UE;transmitting a second signaling to the UE to inform the UE to receivedata directly transmitted from the communication device; andtransmitting the data via the radio resource to the UE.
 17. Thecommunication device of claim 16, wherein the second signaling is aPhysical Downlink Control Channel (PDCCH) or Enhanced Physical DownlinkControl Channel (EPDCCH) signaling or a signaling transmitted via acontrol channel for the proximity service communication.
 18. Thecommunication device of claim 16, wherein an indication of a RadioNetwork Temporary Identifier (RNTI) to be used to de-scramble the datais included in the second signaling.
 19. The communication device ofclaim 16, wherein an indication of power to be used to transmit anacknowledgement for reception of the data is included in the secondsignaling.
 20. The communication device of claim 16, wherein anindication of a key and/or an algorithm to be used to decipher the dataand/or check the integrity of the data is included in the secondsignaling.